1. Technical Field
The present invention generally pertains to an automatic transmission for a motor vehicle. More specifically, but without restriction to the particular embodiment or use which is shown and described for purposes of illustration, the present invention relates to a one-piece annulus gear of a planetary gear set manufactured using a flow forming process.
2. Description Of The Related Art
A conventional automatic transmission includes a hydrodynamic torque converter to transfer engine torque from an engine crank shaft to a rotatable input member of the transmission through fluid-flow forces. The transmission also includes frictional units, typically referred to as clutches or brakes, which couple the rotatable input member to a member of a planetary gear set or hold a member of the planetary gear set stationary during the transmission of power. Such automatic transmissions typically provide for multiple planetary gear sets in order to provide various ratios of torque and to ensure that the available torque and the respective tractive power demand are matched. Thus, the internal components of an automatic transmission are numerous and complex.
There is a continuous effort to optimize the components of the automatic transmission and minimize the weight thereof by the use of lighter weight materials such as aluminum or alternately through improvements in the component design.